Conditioned air vestibule



FIG. 1 is a front perspective view of a conditioned air vestibule showing my new design, the rear perspective view being substantially identical thereto;

FIG. 2 is a top plan view thereof; and

FIG. 3 is a side elevation view thereof, the opposed side being substantially identical thereto. 

The ornamental design for a conditioned air vestibule, substantially as shown and described. 